In recent years, LTE (Long Time Evolution) is becoming widespread as a 3GPP (Third Generation Partnership Project) based wireless communication technology. In LTE, a base station (eNB: evolved Node B) includes a baseband processing device (BBU: Base Band Unit) and a radio processing device (RRH: Remote Radio Head). Also, the baseband processing device and the radio processing device are connected with each other through an optical transmission line (e.g., an optical cable).
Related techniques are disclosed in, for example, Japanese Laid-Open Patent Publication No. 2009-159189.